Research on Downhole Blocking and Acidizing Technology for Low Pressure Oil and Gas Wells in Old Oil and Gas Fields

Abstract

Carboniferous reservoirs in old areas pose significant challenges due to their large depths, often exceeding 3000 m and sometimes reaching up to 5000 m. These wells frequently encountered pressure gradients below 0.5 and in some cases below 0.3. This difficulty in fluid flow makes it challenging to effectively control and stimulate gas production. To address these challenges, we conducted acid stimulation trials using a variety of techniques, including conventional acid, downwelling acid dissociation, and newly tested surfactant acids. Among these techniques, surfactant acids have demonstrated superior dissolution properties in downwelling acid stimulation experiments. Its distinctive properties, such as enhanced flow characteristics and improved performance in low-pressure environments, make surfactants a promising option for future stimulation operations in low-pressure gas wells. In conclusion, our experiments have shown that the use of surfactant acid for down-well acid stimulation in low-pressure gas wells can effectively address the challenges faced in the oil and gas wells in old oil and gas fields. These discoveries have led to the development of more efficient gas production techniques in similar geological formations. Further research and application of surfactant acid can lead to enhanced stimulation results and increased gas recovery in low-pressure gas wells.